RG and Differential has a lot to do with it but for me, it's more about the cover. I will throw to fast, from time to time and a pearl just blows through the breakpoint, or the point I am trying to hit anyway.
BTW, I'm probably part of the 49% that many 'rules' don't apply to as well.
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az guy aka: R & L Bowlers Pro
rlbowlerspro@cox.net